public class 猴子吃桃 {
    public static void main(String[] args) {
        huozi(10);
    }
    public static int huozi(int day){
        int num = 1;
        for (int i = 1; i < day; i++) {
            num = (int)(num+1)*2;
        }
        System.out.println(num);
        return num;

    }
}
